Space heater construction particularly for mobile installations

ABSTRACT

A space heater, particularly of the mobile type for motor vehicles, boats, campers, etc., comprises a tubular support part which provides a support for a drive motor which is arranged centrally therein and which includes a fan at one end for directing combustion air inwardly into the tubular support and into a combustion chamber and also for directing space heating air around the tubular support and around the combustion chamber. A single integral part which is advantageously die cast or molded forms the combustion chamber, a precombustion chamber with a fuel inlet connection and a heat exchanger section with a lateral exhaust discharge. The single part is located within the casing and it includes inwardly extending rib portions of the heat exchanger over which the combustion air passes on the way to the discharge for the combustion air which is located at one end of the outer casing. The drive motor also drives a combustion air fan which is at its end which is opposite to the inlet end and adjacent the inner end of the combustion chamber. A fuel is admitted through the fuel inlet connection to the precombustion chamber which includes means for igniting the fuel, and the combustion chamber includes a perforated flame tube which discharges against the closed end of the heat exchanger so that the combustion gases flow backwardly to a lateral discharge connected to the exhaust pipe.

United States Patent Kofink 1 Jul 15, 1975 SPACE HEATER CONSTRUCTION [57] ABSTRACT PARTICULARLY FOR MOBILE A space heater, particularly of the mobile type for INSTALLATIONS motor vehicles, boats, campers, etc., comprises a tu- 75 Inventor: Siegfried Kofink, Zell (Neckar), hula Support which Pmvides a SUPPO" for a Germany drive motor which is arranged centrally therein and which includes a fan at one end for directing combusl Assigneel Eberspacher, Germany tion air inwardly into the tubular support and into a [22] Filed: Feb 7 1974 combustion chamber and also for directing space [63] Continuation of Ser. No. 297.835, Oct. 16, 1972,

abandoned.

[52] US. Cl. 126/110 B; 126/116 R [51] Int. Cl. F24h 3/06 [58] Field ofSearch 126/110 R, 110 B, 116R [56] References Cited UNITED STATES PATENTS 2.619082 11/1952 Mueller 126/110 B 2,779,398 l/l957 Brown 126/110 R 2787.319 4/1957 Ryder 126/110 R 3,046,973 7/1962 Kofink 126/110 R 3,103,923 9/1963 Kofink 126/116 R 31144862 8/1964 Hottenroth et a1. 4 126/110 R 3.779229 12/1973 Volbehr 126/110 B Primary Examiner-William E. Wayner Assistant Examiner-William E. Tapolcai, Jr. Attorney, Agent, or FirmMcGlew and Tuttle heating air around the tubular support and around the combustion chamber. A single integral part which is advantageously die cast or molded forms the combustion chamber, a precombustion chamber with a fuel inlet connection and a heat exchanger section with a lateral exhaust discharge. The single part is located within the casing and it includes inwardly extending rib portions of the heat exchanger over which the combustion air passes on the way to the discharge for the combustion air which is located at one end of the outer casing. The drive motor also drives a combustion air fan which is at its end which is opposite to the inlet end and adjacent the inner end of the combustion chamber. A fuel is admitted through the fuel inlet connection to the precombustion chamber which includes means for igniting the fuel, and the combustion chamber includes a perforated flame tube which discharges against the closed end of the heat exchanger so that the combustion gases flow backwardly to a lateral discharge connected to the exhaust pipe.

13 Claims, 3 Drawing Figures FATE-WED L 5 I975 if j 74 FIG! FIGS

FIG. 2

SPACE HEATER CONSTRUCTION PARTICULARLY FOR MOBILE INSTALLATIONS This is a streamline continuation of application Ser. No. 297,835 filed Oct. 16, 1972, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to the construction of combustion devices and, in particular. to a new and useful small size space heater, particularly for mobile units, such as motor vehicles, boats, campers. and the like which has a construction which includes an integral single part which defines the combustion chamber, antechamber, heat exchanger with indirect heating sur faces, and an exhaust pipe connection.

2. Description of the Prior Art In the known heaters, the heat exchanger portion is formed of plates which are welded together and which is secured to a combustion chamber portion such as by welding or soldering and the combustion chamber itself includes a separate part forming a precombustion chamber or antechamber which is welded to it. Most of the known heat exchangers are provided with indirect heat surfaces on only a single side since a welded joint on the corresponding indirect heating surface on both sides of the heat exchanger is not economical in view of the large amount of manual work which is required to form the part. This is true even though the use of indirect heating surfaces on both sides provides a better utilization of the heat generated in the combustion chamber by the fuel which is burned. The known heaters of this type have been produced for a long time and distributed in large quantities, and they have also required a certain maturity in their operation. Nevertheless, no satisfactory solution has been found in respect to the creation of a combustion device which does not involve so much manual labor in the assembly of the heater.

SUMMARY OF THE INVENTION The present invention provides a space heater which is constructed in a manner such that the manual work for producing it is considerably reduced over that of the conventional heaters which are known at the present time. Nevertheless, the heater of the invention may be constructed in a small size and with an efficiency which is greater for this size than the known devices. Alternatively, the heater of the invention can have an improved efficiency and output, but with the same volume as the known devices. The invention is based on the finding that a number of elements of the heater can be combined into a single part which can be manufactured to minimum dimension sizes but with maximum efficiency. On the basis of the finding of theinvention, a heater is provided which includes a combustion chamber formed of a single integral part which includes a precombustion and combustion chamber portion and a heat exchanger portion with an exhaust pipe connection to the heat exchanger portion. All of these parts are formed of a single die cast or injection molded part. A material for such a die cast part advantageously comprises an aluminum alloy for example, a siliumin, instead of the normally used high grade iron plates. Such a die cast part not only has the desired advantages, but also requires relatively little manual work to assemble. Surprisingly, the die cast part may be combined with the remaining portion of the space heater and the die cast part may be produced with relatively few molds even though it combines many different functional portions. With the inventive arrangement, it is possible and also preferable that the fuel feed pipe also comprise a plastic part. In this arrangement, the guide ducts for A further object of the invention is to provide an inexpensive space heater which includes a single integral part which forms an antechamber, an inlet fuel connection. a combustion chamber, and a heat exchanger with a lateral exhaust gas discharge, and which is advantageously made of a die cast or injection molded material such as aluminum alloy.

A further object of the invention is to provide a space heater which is simple in design, rugged in construction. and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention. its operating advantages and specific objects attained by its uses. reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is an axial longitudinal section through a heater constructed in accordance with the invention:

FIG. 2 is a section takenon the line IIlI of FIG. I; and

FIG. 3 is a section taken on the line IIIIII of FIG. I.

GENERAL DESCRIPTION oF THE PREFERRED EMBODIMENT Referring to the drawings in particular, the invention embodied therein, comprises a heater, generally designated l0, ofa type which is adapted for use with mobile units, such as motor vehicles, boats, campers, etc. The heater includes a support pieceor tubular support part, generally designated 22, which provides a mounting for a centrally positioned electric motor 12 which drives a radial fan 16 which is designed as a radial and diagonal wheel carried on a shaft 14 at one end of the motor. The motor 12 also drives a combustion air fan 20, carried on a shaft 18, at the other end. The entire unit, comprising the electric motor 12, with the fan 16, and the fan 20, are held by the supporting part at a spaced location from its interior wall.

In accordance with the invention, the heater includes a single integral part, generally designated 28, in the form of a hollow tubular member, which is rigidly secured to the supporting part 22 by three circumferentially spaced screw bolts 24, which are distributed around an end flange 26 of the single part 28. The single part 28 is made of silumin, and is aligned with the axis of the motor 12 and the axis of the support part 22.

3 The single integral part 28 forms a combustion chamber 30, and antechamber 32, which extends laterally outwardly therefrom, and a fuel pipe connection 34,

which extends into the antechamber 32. In addition,

the single integral part 28 also includes a heat exchanger portion forming an axial extension of the combustion chamber 30 and which includes indirect heating surfaces 38 on the interior and outer indirect heating surfaces 40 and also includes a lateral exhaust pipe connection 42. The exhaust pipe connection extends forwardly of the plane of the antechamber 32.

Adjacent the combustion chamber. there is provided two insert plates 44 and 46 which provide guides for the combustion air on the way to the combustion chamber 30. These insert plates can be welded on the supporting part 22, if desired. The supporting part 22 also carries a lateral inlet pipe connection 48 for the combustion air. The combustion air fan carries a metal cap 50 which rotates with the fan and which includes an end face 52 forming an axial terminal wall of the combustion chamber 30. A ring nozzle 54 is located between the insert plate 46, and the circumference of the metal cap 50, and combustion air flows axially into the combustion chamber through a ring nozzle 54 and mixes with liquid fuel which is supplied through the fuel feed connection 34 in the antechamber 32. The combustion air enters at first in a radial direction as it flows through the inlet pipe 48, and it cools the electric motor 12 inside the chamber 56 which is enclosed by the supporting part 22. This air turns in the direction of the arrow 58 ahead of the insert plate 44 and moves radially inwardly and passes through openings 60 of the insert plate 44 in the axial direction. It is then conveyed radially to the outside between the insert plate and the bladed disc 62 of the combustion air fan 20 and is conducted in an annulus between the metal cap 50 and the insert plate 46 along baffle plate 64 obliquely inwardly back to the ring nozzle 54.

In the antechamber 32 is arranged a spark plug assembly, generally designated 66. The spark plug assembly 66 comprises an ignition means for igniting the combustion air and fuel mixture in the combustion chamber 30.

An insert 68 of metal is welded to the insert plate 46 and it extends first along the inner lining of the die cast part 28 and then is directed inwardly in a funnel form at the interior of the combustion chamber and terminates in -a tubular extension extending outwardly away from the end face 52 of the metal cap 50 and forms a heat resistant boundary enclosing the combustion chamber 30. A flame tube 72 made of a heat resistant sheet metal is welded to the tubular extension 70 and it includes several rows of openings 74 extending parallel in a longitudinal direction and which are arranged in staggered parallel rows. The flame tube 72 protrudes into a cylindrical coil recess 76 of the die cast part 28 and it is spaced inwardly from the indirect heating surfaces 38 of the heat exchanger section 36. The flame tube 72 is maintained in spaced radial arrangement in respect to the indirect heating surfaces 38. The exhaust gases can thus pass axially through the flame tube 72 and flow along its circumference to cover the indirect heating surfaces 38 of the heat exchanger 36 and then it flows through the exhaust pipe connection 42. The path to the exhaust pipe connection 42 is shortened by passing through the opening 74 and this avoids a resonance phenomena.

The respectiveaxially extending indirect heating surfaces 38 and 40 extend over different lengths with the inner indirect surface 38 starting only behind the exhaust pipe connection 42 and extending over the entire length of the interior space 76 of the heat exchanger section 36. The indirect heating surface 38 has a somewhat wider extension in the direction of the combustion chamber 30 beyond'the width of the exhaust pipe connection 42, and this outer indirect heating surface 40 starts adjacent the antechamber 32 and extends at the opposite end around rounded end of the die cast part 28. An advantageous form of the indirect heating surface results in the construction shown in FIGS. 2 and 3. In this arrangement, the outer indirect heating surfaces 40 are formed by longitudinal fins of equal radial height which are distributed evenly over the circumference of the heat exchanger 36. The inner indirect heating surfaces 38 are also formed by longitudinal fins distributed evenly over the circumference of the heat exchanger but include alternate fins of different heights with a height being in a ratio of about 1:2 be

tween alternately adjacent fins. As can be seen further from FIG. 1, the exhaust pipe connection 42 passes out through the indirect heating surfaces 36. The construction of the heater 10 is axially symmetrical with the exception of the lateral extensions provided for the inlet 48 and the exhaust 42.

An outer symmetrical jacket or casing 80 is clamped on the die cast body part 28 and forms an outer surrounding casing or housing having an inlet 82 adjacent the fan 16 at one end and a discharge for space air 84 at the opposite end. A jacket 80 is made of a plastic material and the interior surface defines a base heating air flow space surrounding the fixed support 22 and the integral one piece part 28 to permit flow of air to be heated past the heat exchanger section 36 where it is heated so that it may be used for space heating when it flows out of the exit 84. The inlet 82 in the discharge 84 are formed of identical tubular parts and each includes an outwardly flaring part which engages over two halve shell portions 88 and 90 which form the central jacket 80. The centering of the jacket is effected by attaching it on the lateral extensions of the antechamber 32 and the exhaust pipe connection 42 of the integral one piece part 28 so that only one connection has to be established between the four elements 86, 88, and 90 forming the jacket at points 92, 94 and this may be made by securing screws, for example. In addition, suitable packing is provided as necessary. One half shell 88 of the jacket carries an electrical connecting part for the electric motor 12, but this is not shown.

The integral one piece part 28 requires relatively little reworking for example, for the application of screw threads for the screw bolts 24 carried on the flange 26. The parts which are connected directly and indirectly with the supporting part 22 can be inserted jointly into the die cast part 28 from the left, as shown in FIG. 1, and then only the jacket 80 has to be secured. Preferably, the lateral extensions of the die cast parts are made slightly conical in order to facilitate the centering of the cover 80 on the integral die cast part 28.

The heater 10 can be detachably mounted on any mobile unit in a simple manner, for example. with the rubber bands and roller braces. and it is fully operable both inhorizontal and vertical, and in any inclined position as a self-sufficient heater. Apart from cables and overheating switches. the heater 10 can be smooth on the outside. A short type motor can be used for the electric motor 12 and the ignition includes a glow ignition of conventional type. but a spark ignition can be provided.

While a specific embodiment of the invention has been shown and described in detail to illustrate the aprounding most of the length of said motor and spaced radially outwardly therefrom to define an air flow space therebetween and terminating in an inner flanged end. an outer casing surrounding said tubular support part and spaced outwardly therefrom defining an air inlet at one end and extending beyond said support part at its opposite end and terminating at the opposite end in a space heating air discharge, a hollow tubular single integral part having a mounting flange bolted to and axially aligned with said tubular support part flanged end and defining a lateral antechamber having a fuel feed connection with igniter means for igniting the fuel and also defining a central combustion chamber section and an inner and outer ribbed heat exchanger section with a closed outer end and being located within and spaced from said casing and having an exhaust pipe connection spaced inwardly from the enclosed end for exhausting the gases generated in said combustion chamber, said tubular support part having a combustion air inlet to said combustion chamber, the space between said outer casing and said support part, said combustion chamber and said heat exchanger section, defining a flow space for space heating air flow from said space heating inlet to said space heating air outlet, at least one thermostable insert having a radially extending flange connected between said flange end of said support part and said mounting flange of said single integral part and forming an outer guide wall for the combustion air and flame guide means extending from said combustion chamber toward the closed end of said integral part but being spaced axially from said closed end and inwardly from said heat exchanger section to permit exit of the combustion gases therefrom and flow thereof in contact with said heat exchanger section.

2. A space heater, particularly of the mobile type for motor vehicles, boats. campers, etc., comprising a tubular support part, a drive motor in said support part having a rotatable inlet fan for the inflow of space air to be heated around said support part, said tubular support part supporting most of the length of said motor and spaced radially outwardly therefrom to define an air flow space therebetween and terminating in an inner flanged end, an outer casing surrounding said tubular support part and spaced outwardly therefrom defining an air inlet at one end and extending beyond said support part at its opposite end and terminating at the opposite end in a space heating air discharge, a single integral part having a mounting flange bolted to said tubular support part flanged end and defining an antechamber having a fuel feed connection with igniter means for igniting the fuel and also defining a combus- LII tion chamber section and an inner and outer ribbed heat exchanger section located within and spaced from said casing and having an exhaust pipe connection for exhausting the, gases generated in said combustion chamber, said tubular support having a combustion air inlet. to said combustion chamber. the space between said outer casing and said support part, said combustion chamber and said heat exchanger section. defining a flow space for space heating air flow from said space heating inlet to said space heating air outlet. said drive motor including said rotatable inlet fan at one end for the inflow of space air to said space air inlet and a combustion air fan at its opposite end for the inflow of combustion air having a centrally arranged guide wall. and an annular thermostable insert having a radially extending flange disposed between said flanged end of said support part and said mounting flange of said integral part and extending into said combustion chamber and being adjacent said combustion air fan in spaced relation to said guide wall and extending inwardly from said single integral part and defining a flow passage with said guide wall for the flow of combustion air into the combustion chamber.

3. A space heater. according to claim 2, wherein said single integral part comprises a die cast or injection molded part.

4. A space heater. according to claim 2, wherein said fuelfeed pipe connection is formed integrally with said single integral part which comprises a single die cast part.

5. A space heater, according to claim 2, wherein said insert is thermostable and is arranged at the higher temperature stress points of said integral part.

6. A space heater. according to claim 5. wherein said insert is cast into said integral part.

7. A space heater, according to claim 5, wherein there are two concentrically arranged inserts adjacent said combustion air fan forming a ring passage for combustion air and being connected to said single integral part adjacent the end thereof connected to said tubular support part. said inserts comprising heat proof plates.

8. A space heater, according to claim 2. wherein said outer casing comprises a plastic jacket secured to said integral part and spaced from the outer wall of said integral part.

9. A space heater. according to claim 8, wherein said jacket is formed of two half-shell portions and an end cap surrounding each half-shell portion at each end and defining a space air inlet at one end and a space air outlet at the opposite end.

10. A space heater, according to claim 9, wherein said end caps are of identical configuration and engage over the periphery of said shell portions forming said outer casing.

11. A space heater, according to claim 2, wherein said antechamber extends laterally outwardly from said combustion chamber.

12. A spacer heater, according to claim 2, wherein said exhaust pipe connection includes a laterally extending pipe formed integrally with said single integral part.

13. A space heater, according to claim 2, wherein said heat exchanger part comprises an axial extension of said combustion chamber and it includes separate indirect heating surfaces on the interior and separate indirect heat exchanger surfaces on the exterior, said exhaust pipe extending laterally and piercing through the outer indirect heating surfaces in a direction extending inwardly toward said combustion chamber. 

1. A space heater, particularly of the mobile type for motor vehicles, boats, campers, etc., comprising a tubular support part, a drive motor carried by and located in said tubular support part having a rotatable inlet fan for the inflow of space air to be heated around said tubular support part, said tubular support part surrounding most of the length of said motor and spaced radially outwardly therefrom to define an air flow space therebetween and terminating in an inner flanged end, an outer casing surrounding said tubular support part and spaced outwardly therefrom defining an air inlet at one end and extending beyond said support part at its opposite end and terminating at the opposite end in a space heating air discharge, a hollow tubular single integral part having a mounting flange bolted to and axially aligned with said tubular support part flanged end and defining a lateral antechamber having a fuel feed connection with igniter means for igniting the fuel and also defining a central combustion chamber section and an inner and outer ribbed heat exchanger section with a closed outer end and being located within and spaced from said casing and having an exhaust pipe connection spaced inwardly from the enclosed end for exhausting the gases generated in said combustion chamber, said tubular support part having a combustion air inlet to said combustion chamber, the space between said outer casing and said support part, said combustion chamber and said heat exchanger section, defining a flow space for space heating air flow from said space heating inlet to said space heating air outlet, at least one thermostable insert having a radially extending flange connected between said flange end of said support part and said mounting flange of said single integral part and forming an outer guide wall for the combustion air and flame guide means extending from said combustion chamber toward the closed end of said integral part but being spaced axially from said closed end and inwardly from said heat exchanger section to permit exit of the combustion gases therefrom and flow thereof in contact with said heat exchanger section.
 2. A space heater, particularly of the mobile type for motor vehicles, boats, campers, etc., comprising a tubular support part, a drive motor in said support part having a rotatable inlet fan for the inflow of space air to be heated around said support part, said tubular support part supporting most of the length of said motor and spaced radially outwardly therefrom to define an air flow space therebetween and terminating in an inner flanged end, an outer casing surrounding said tubular support part and spaced outwardly therefrom defining an air inlet at one end and extending beyond said support part at its opposite end and terminating at the opposite end in a space heating air discharge, a single integral part having a mounting flange bolted to said tubular support part flanged end and defining an antechamber having a fuel feed connection with igniter means for igniting the fuel and also defining a combustion chamber section and an inner and outer ribbed heat exchanger section located within and spaced from said casing and having an exhaust pipe connection for exhausting the gases generated in said combustion chamber, said tubular support having a combustion air inlet to said combustion chamber, the space between said outer casing and said support part, said combustion chamber and said heat exchanger section, defining a flow space for space heating air flow from said space heating inlet to said space heating air outlet, said drive motor including said rotatable inlet fan at one end for the inflow of space air to said space air inlet and a combustion air fan at its opposite end for the inflow of combustion air having a centrally arranged guide wall, and an annular thermostablE insert having a radially extending flange disposed between said flanged end of said support part and said mounting flange of said integral part and extending into said combustion chamber and being adjacent said combustion air fan in spaced relation to said guide wall and extending inwardly from said single integral part and defining a flow passage with said guide wall for the flow of combustion air into the combustion chamber.
 3. A space heater, according to claim 2, wherein said single integral part comprises a die cast or injection molded part.
 4. A space heater, according to claim 2, wherein said fuel feed pipe connection is formed integrally with said single integral part which comprises a single die cast part.
 5. A space heater, according to claim 2, wherein said insert is thermostable and is arranged at the higher temperature stress points of said integral part.
 6. A space heater, according to claim 5, wherein said insert is cast into said integral part.
 7. A space heater, according to claim 5, wherein there are two concentrically arranged inserts adjacent said combustion air fan forming a ring passage for combustion air and being connected to said single integral part adjacent the end thereof connected to said tubular support part, said inserts comprising heat proof plates.
 8. A space heater, according to claim 2, wherein said outer casing comprises a plastic jacket secured to said integral part and spaced from the outer wall of said integral part.
 9. A space heater, according to claim 8, wherein said jacket is formed of two half-shell portions and an end cap surrounding each half-shell portion at each end and defining a space air inlet at one end and a space air outlet at the opposite end.
 10. A space heater, according to claim 9, wherein said end caps are of identical configuration and engage over the periphery of said shell portions forming said outer casing.
 11. A space heater, according to claim 2, wherein said antechamber extends laterally outwardly from said combustion chamber.
 12. A spacer heater, according to claim 2, wherein said exhaust pipe connection includes a laterally extending pipe formed integrally with said single integral part.
 13. A space heater, according to claim 2, wherein said heat exchanger part comprises an axial extension of said combustion chamber and it includes separate indirect heating surfaces on the interior and separate indirect heat exchanger surfaces on the exterior, said exhaust pipe extending laterally and piercing through the outer indirect heating surfaces in a direction extending inwardly toward said combustion chamber. 